AR 15 - 20" or 16" barrel?

[J&J]

My son was asking if there is a significant difference in accuracy out of an AR-15 with a 20" barrel vs. a 16" barrel. I told him that I thought the 5.56 round was originally intended for the 20" barrel, but other than that I don't know what the difference might be or if that matters.

Anyone here that can answer that question? Real experience or armchair knowledgewould be fine.

Thanks

John

 

[ugaarguy]

Inside of 500 yards there's no difference to speak of accuracy wise. Beyond those ranges the longer sight radius and slightly higher velocities of the 20" bbl are helpful. Using a barrel with the proper twist for the bullet weight you intend to shoot will have more affect on accuracy than barrel length.

 

[clemsonu0219]

How long have you been shooting and how much would be my question. I would think that unless you are very accurate @ 100, 300, 500 yards it shouldn't make a huge difference.

Maybe I'm wrong.

 

[Byron]

The original in the mid 60's was a 20" barrel. A shorter version was made.I do not recall the barrel length but appeared to be 14". The vast majority of troops had the 20". Byron

 

[P.B.Walsh]

I belive that the only concern is the loss in velocity, I don't think that the barrel lengh has anything to do with accuaccy.

This is only what i've heard.

 

[minutemen1776]

With iron sights, I am able to shoot more accurately with a 20-inch barrel. For me, the longer sight radius helps even at relatively short ranges. But I still like my 16-inch collapsible-stock M4gery for its handiness. The shorter barrel is sufficiently accurate, but the 20-incher is just a tad better for me.

 

[SSN Vet]

you take 4" off the length of the rifle and lose very little by way of ballistic performance inside 300 yds.

Are you planning on waxing yutes at 600 yds. ?

if not get the 16" is mho.

 

[EdLaver]

If you plan on using the rifle at distances of 400-600 yards then the 20" will be ideal, any thing less then definetly the 16" can handle it.

 

[brian923]

go 18" spr white oak armament. i did, and its an awsome barrel.

stiffness and regidity will affect accuracy. a bull barrel, 16" vs. a 20 pencile barrel will usually have better accuracy. all things aside though, unless you plan to shoot real far, and real small groups, barrel length is more of a preferenace.

 

[ArmedBear]

Accuracy notwithstanding, a 16" carbine and a 20" rifle feel pretty different from each other.

Like brian923 said, it's more of a preference.

If you can, shoulder the guns first and figure out whether you prefer something that feels like a rifle, or a carbine.

 

[HJ857]

A standard load with a 55 to 69 grain bullet will give you a maximum supersonic range of around 650 yards, the extra velocity potential of the 20" barrel will give you the greatest range, but not by a lot.

I think most of the responses are missing an important point and that is barrels are made for different purposes. For example, a standard Bushmaster M4 barrel is not going to anywhere near as accurate as the White Oak SPR, as brian923 listed. Same for any match barrel or varmint barrel or DMR barrel, etc.

This is sort of an apples vs oranges argument. You need to narrow it down to whether you want to compare a basic barrel which is likely made for a "combat accuracy" use or a barrel made for bench/varmint/match accuracy.

 

[sarduy]

it's this simple....

the 16'' will do anything a 20'' do with the right bullet/twist/scope combination.

 

[J&J]

Great answers all around. We do not get the opportunity to shoot at rannges above 100 yards very often, so it sounds like it should not make a difference. Maybe, as stated above it will be just as important to find what "feels" right to him. Mostly it was just a curiosity matter. Gladly this is where his 14 year old curiosity is

Thanks for the answers.

John

 

[dispatch55126]

For a 14 YO, sit him down with a quality M16/M4/AR15 book, ask him what looks best to him and enjoy. Also, you never said if he likes to build things. If he does, building a M16A1 clone may be very rewarding. If he's only looking for something to shoot, any M4gery will do.

Visit this site: http://www.ar15.com/forums/forum.html?b=3&f=123 for more ideas on retro AR's.

 

[Dr. Tad Hussein Winslow]

My son was asking if there is a significant difference in accuracy out of an AR-15 with a 20" barrel vs. a 16" barrel

NO. Barrel length affects external and terminal performance, and rifle weight & balance, and report/blast, not accuracy. Barrel PROFILE/THICKNESS can affect accuracy, but not length (at least not the difference in *those* two lengths).

I told him that I thought the 5.56 round was originally intended for the 20" barrel,

YES.

but other than that I don't know what the difference might be or if that matters.

Doesn't matter a great deal at most ranges, other than a 20" being quieter and having less recoil, and a 16" being lighter/handier/better balanced.

At long ranges (past 200 yards or so), the extra velocity gained from the 20" barrel can help with terminal performance and practical accuracy (wind bucking). With certain bullet weights and constructions, the 20" can even help with terminal performance at short ranges.

Got one of each. The 20" is the range plinking gun & hunting AR, and the 16" is the fighting gun.

 

[SHvar]

Depends, the 20" is easier to shoot accurately (less recoil, quieter, less muzzle flash), especially if shooting on a bench, bipod, sandbags, etc.
The 16" is easier to hold, weighs less, fits through smaller spaces.
Realistically the range at which the A2/A3 model 20" is accurate is 400 meters point targets/800 meters area targets. The 16" carbine has sights set for 300 meters point target/600 meters area target.
I personally like the carbine size, but enjoy shooting the rifle size at targets sometimes.
My good friends Hbar is amazingly accurate, my carbines are very accurate, but more of a challenge to shoot accurately at the same distances.

 

[Jeff White]

A shorter version was made.I do not recall the barrel length but appeared to be 14".

Byron,
The XM177E2 had an 11.5 inch barrel with a Colt designed noise/flash suppressor which gave the barrel an overall length of around 14 inches. In the mid 1970s the BATF ruled that the noise/flash suppressor was a true silencer and the Carter administrations export restrictions on silencers forced Colt to drop it from the catalog.

I fired the Air Force version GAU5 once and it had about the same report as a 20" rifle so the noise/flash suppressor didn't suppress much.

 

[RockyMtnTactical]

Very little difference accuracy wise. The 20" gives a couple hundred FPS from the muzzle is all.

 

[dscottw88]

I think I remember reading that the standard 55gr round will reliably fragment out to about 200 yards in the 20" barrel. And about 150 yards with the 16" barrel.

Unless your shooting in match competitions where .0034" of an inch makes the difference of win or lose, I'd stick with the 16" barrel.

 

[Nowhere Man]

Most shooters will get better accuracy with a 20" bull barrel vs a 16" regular barrel.

The heavier the rifle, the less chance it will move.


Dave

 

[Lovesbeer99]

Split the difference and get the 18" barrel.

I have the 20 and I like shooting open sights. If I had a 16 I'd probably put a red dot or optic on it. What does your son plan to do?

 

[mcdonl]

Dad.... get me one with a 20" ok?

 

[minutemen1776]

If you and your 14-year-old son get a chance to handle a few different ARs, make sure you try different barrel contours if at all possible. It seems that most 20-inchers these days are heavy barrels, which easily add an extra pound of weight to the muzzle end. This may be fine from the bench, but the longer HBARs otherwise feel unbalanced to me. The 20-incher I have is a government profile, which basically has a slimmer contour under the handguards. As far as weight goes, it's about the same as my 16-inch HBAR. Frankly, I like the feel of both. Again, though, I just think the 20-incher's sights are a bit easier to use, whereas the 16-incher is a little handier.

 

[Dr. Tad Hussein Winslow]

Most shooters will get better accuracy with a 20" bull barrel vs a 16" regular barrel.

Yes, but they will also get just as good of accuracy from a 16" bull as a 20" bull, and from a 16" lightweight as a 20" lightweight - so you're exactly right, but that's a function of barrel profile, not length.

 

[Art Eatman]

Summary: There is no inherent difference in accuracy between the 16" and the 20" barrels. Some people can shoot more accurately with one than the other, but that's a function of the person, not the rifle.